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TROJ_DROPPR.FB

June 09, 2011
 Analysis by: Sabrina Lei Sioting
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW


This malware leverages the anticipated Apple's iPhone 5 as a social engineering hook. Spammed messages with a subject referring to the availability of iPhone 5 in black were found to contain a link that leads to the download of this malicious file.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

  TECHNICAL DETAILS

File Size:

1,412,334 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

08 Jun 2011

Payload:

Drops files

Arrival Details

This Trojan may be downloaded from the following remote sites:

  • http://{BLOCKED}.{BLOCKED}.229.96/iphone5.gif.exe
  • http://{BLOCKED}.{BLOCKED}.252.37/iphone5.gif.exe
  • http://{BLOCKED}planet.com/iphone5.gif.exe
  • http://{BLOCKED}an.com/iphone5.gif.exe
  • http://{BLOCKED}ersite.com/iphone5.gif.exe

This malware arrives via the following means:

  • It arrives as a link found in email messages spammed by other malware/grayware or malicious users:
    • http://{BLOCKED}ound.com/iphone5.gif.exe

Installation

This Trojan drops the following file(s)/component(s):

  • %Windows%\Temp\Cookies\aliases.ini
  • %Windows%\Temp\Cookies\away.txt - list of possible messages to be sent when irc is idle
  • %Windows%\Temp\Cookies\control.ini
  • %Windows%\Temp\Cookies\fullname.txt - list of possible fullnames to be used in connect dialog
  • %Windows%\Temp\Cookies\grup - used to create a random "nick" in mirc.ini
  • %Windows%\Temp\Cookies\image.jpg - image displayed to make this application appear that it is legitimate
  • %Windows%\Temp\Cookies\main
  • %Windows%\Temp\Cookies\point.ico
  • %Windows%\Temp\Cookies\daemon.exe - legitimate mIRC client

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

It creates the following folders:

  • %Windows%\Temp\Cookies
  • %Windows%\Temp\Cookies\download
  • %Windows%\Temp\Cookies\logs
  • %Windows%\Temp\Cookies\sounds

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\WinRAR SFX

HKEY_CURRENT_USER\Software\mIRC\
Channels

HKEY_CURRENT_USER\Software\mIRC\
LockOptions

Dropping Routine

This Trojan drops the following files:

  • %Windows%\Temp\Cookies\catchme.bat - detected by Trend Micro as BAT_FLOODER.AF
  • %Windows%\Temp\Cookies\crime.mrc - detected by Trend Micro as IRC_FLOODER.VI
  • %Windows%\Temp\Cookies\hmain.exe - detected by Trend Micro as TROJ_BIRTTA.A
  • %Windows%\Temp\Cookies\lock.exe - detected by Trend Micro as TROJ_BIRTTA.A
  • %Windows%\Temp\Cookies\mirc.ini - detected by Trend Micro as IRC_FLOODER.AA
  • %Windows%\Temp\Cookies\ok.mrc - detected by Trend Micro as IRC_FLOODER.VI
  • %Windows%\Temp\Cookies\remote.ini - detected by Trend Micro as IRC_FLOODER.VI
  • %Windows%\Temp\Cookies\servers.ini - detected by Trend Micro as IRC_FLOODER.VI
  • %Windows%\Temp\Cookies\smain.exe - detected by Trend Micro as TROJ_BIRTTA.A
  • %Windows%\Temp\Cookies\temporarly.reg - detected by Trend Micro as REG_FLOODER.BS
  • %Windows%\Temp\Cookies\unlock.exe - detected by Trend Micro as TROJ_BIRTTA.A

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

NOTES:
This Trojan executes catchme.BAT, detected as BAT_FLOODER.AF, to create registries and execute daemon.EXE every system startup. It opens the image.JPG in order to trick the user that the application is legitimate.

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

8.210.09

FIRST VSAPI PATTERN DATE:

08 Jun 2011

VSAPI OPR PATTERN File:

8.211.00

VSAPI OPR PATTERN Date:

09 Jun 2011

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Remove malware files dropped/downloaded by TROJ_DROPPR.FB

Step 3

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\WinRAR
    • SFX
  • In HKEY_CURRENT_USER\Software\mIRC\
    • Channels
  • In HKEY_CURRENT_USER\Software\mIRC\
    • LockOptions

Step 4

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.  
  • %Windows%\Temp\Cookies

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPPR.FB. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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